Online information sources are now frequently updated and corrected by users of the information. All kinds of information on-line is editable by any user, such as business directories, maps, community pages, FAQs, and many other types of information. However that creates the problem of determining the accuracy of user-provided information. Users may be incorrect either on purpose or because the user is mistaken. For example, in the case of a phone number for a business, a user may wish to direct callers to a competing business and provide the competing business' phone number. Alternatively, the user may, as a prank, provide a completely unrelated phone number. Such intentionally incorrect information is unreliable and is also referred to as “spam.”
Unreliable information is becoming more and more of a problem. Malicious users can intentionally mislead others using computer programs that repeatedly change the value of a map attribute to an unreliable value, even as other users correct the unreliable value.
In some approaches to assessing accuracy of user-provided information, expert reviewers assess the information. This however is laborious and time consuming. In extreme cases, it would require a reviewer to physically go somewhere to verify information. Under this approach, it may take days or weeks for incorrect or out-of-date information to be updated.
Errors from incorrect and outdated information lead to very frustrating experiences for users. For example, a user may obtain the phone number for a business from an on-line business directory. If that phone number is wrong, the user will not be able to contact the business. If the number is intentionally incorrect, for example the listed phone number is the phone number of a competing business, the user may even be mislead into contacting a business with whom they did not intend to do business.